Study Finds Solvent Ups Parkinson’s Risk

Weâ€™ve long written about links between various substances and Parkinsonâ€™s disease. Now, the BBC reports that an international study has found a link between an industrial solvent and the progressive, degenerative central nervous system disorder, Parkinsonâ€™s disease.

Parkinsonâ€™s disease usually affects motor skills and speech, among other functions and, while not fatal, complications can be deadly. The cause is unknown and there is no cure. About 180 in every 100,000 Americans are diagnosed with the disease.

Researchers found a massive six-fold increased risk for developing Parkinsonâ€™s in people exposed to trichloroethylene (TCE) in the workplace. And, although mostly banned worldwide, TCE is used as a degreaser, said the BBC. TCE was used in paints, glue, carpet cleaners, and dry-cleaning solutions and was banned in the food and pharmaceutical industries in most areas of the world the 1970s, said the BBC. Although still used as a degreaser, in 1997, TCE was banned as an anesthetic, skin disinfectant, grain fumigant, and coffee decaffeinater in the U.S.

The research involved an analysis of 99 twin pairs chosen from United States data records; researchers from institutes in the U.S., Canada, Germany, and Argentina, were reviewing solvent exposure impact and looked at six substances, including TCE, said the BBC. For each set of twins, one was diagnosed with Parkinsonâ€™s and one was not, noted the BBC.

Twins are believed to be genetically similar or identical and can share some lifestyle characteristics; the researchers felt twins would allow for a better control group, said the BBC. The pairs were interviewed to create work history and determine the likelihood of solvent exposure, according to the BBC. Hobbies were also discussed.

The findings are presented as the first study to report a “significant association” between TCE and Parkinson’s, the BBC explained. The study reviewed exposure to the solvents perchloroethylene (PERC) and carbon tetrachloride (CCl4), both of which, said the team, “tended towards significant risk of developing the disease,” wrote the BBC. A statistical link was not found with toluene, xylene, and n-hexane, the other three solvents reviewed.

“Our study confirms that common environmental contaminants may increase the risk of developing Parkinson’s, which has considerable public health implications,” said Dr. Samuel Goldman of The Parkinson’s Institute in Sunnyvale, California, who co-led the study, said the BBC. The study appears in the journal Annals of Neurology. “Our findings, as well as prior case reports, suggest a lag time of up to 40 years between TCE exposure and onset of Parkinson’s, providing a critical window of opportunity to potentially slow the disease before clinical symptoms appear,” Dr. Goldman added.

Weâ€™ve written that, over the past several years, the agricultural pesticide paraquat has been linked to Parkinsonâ€™s, posing a risk to agricultural workers who toil in fields where the pesticide is sprayed as well as to people living near the fields. Other research revealed that people exposed at their workplaces to ziram, maneb, and paraquat tripled their risk of Parkinsonâ€™s; workplace exposure to both ziram and paraquat nearly doubled Parkinsonâ€™s risk; and people who worked with either paraquat or the pesticide rotenone were 2.5 times more likely to develop Parkinsonâ€™s.

Another study found that some medications, notably the amphetamines Benzedrine or Dexedrine, used to treat attention deficit hyperactivity disorder (ADHD) to help patients achieve more defined focus and increase clarity and awareness, could also place those patients at risk for Parkinsonâ€™s disease.